import launch
import launch.event_handlers
import launch.launch_description_sources
import launch_ros
from ament_index_python.packages import get_package_share_directory
import os

import launch_ros.parameter_descriptions

def generate_launch_description():
    # 获取功能包share路径
    urdf_package_path = get_package_share_directory('fishbot_description')
    default_xacro_path = os.path.join(urdf_package_path,'urdf','fishbot/fishbot.urdf.xacro')
    # default_rviz_config_path =  os.path.join(urdf_package_path,'config','display_robot_model.rviz')
    default_gazebo_world_path =  os.path.join(urdf_package_path,'world','custom_room.world')
    # 声明一个urdf目录的参数，方便修改
    action_declare_arg_mode_path = launch.actions.DeclareLaunchArgument(name='model',default_value=str(default_xacro_path),description='加载的模型文件路径')
    # 通过文件路径，获取内容，并转换成参数值对象，以供传入robot_state_publisher  后面有个空格
    substitutions_command_result=  launch.substitutions.Command(['xacro ',launch.substitutions.LaunchConfiguration('model')])
    robot_description_value = launch_ros.parameter_descriptions.ParameterValue(substitutions_command_result,value_type=str)

    action_robot_state_publisher=launch_ros.actions.Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        parameters=[{'robot_description':robot_description_value}]
    )

    action_launch_gazebo = launch.actions.IncludeLaunchDescription(
        launch.launch_description_sources.PythonLaunchDescriptionSource(
            [get_package_share_directory('gazebo_ros'),'/launch','/gazebo.launch.py']
        ),
        launch_arguments=[('world',default_gazebo_world_path),('verbose','true')]
    )

    action_spawn_entity = launch_ros.actions.Node(
        package='gazebo_ros',
        executable='spawn_entity.py',
        arguments=['-topic','/robot_description','-entity','fishbot']
    )

    # action_load_joint_state_controller = launch.actions.ExecuteProcess(
    #     cmd=['ros2 control load_controller --set-state active fishbot_joint_state_broadcaster'.split(' ')],
    #     output='screen'
    # )
    # 加载并激活 fishbot_joint_state_broadcaster 控制器
    action_load_joint_state_controller = launch.actions.ExecuteProcess(
        cmd=['ros2', 'control', 'load_controller', '--set-state', 'active',
            'fishbot_joint_state_broadcaster'],
        output='screen'
    )

     # 加载并激活 fishbot_effort_controller 控制器
    action_load_effort_controller = launch.actions.ExecuteProcess(
        cmd=['ros2', 'control', 'load_controller', '--set-state', 'active','fishbot_effort_controller'], 
        output='screen')

    #加载并激活fishbot_diff_drive_controller控制器
    action_load_diff_driver_controller = launch.actions.ExecuteProcess(
        cmd=['ros2', 'control', 'load_controller', '--set-state', 'active','fishbot_diff_drive_controller'], 
        output='screen')

    # action_rviz_node=launch_ros.actions.Node(
    #     package='rviz2',
    #     executable='rviz2',
    #     arguments=['-d',default_rviz_config_path]
    # )

    return launch.LaunchDescription([
        action_declare_arg_mode_path,
        action_robot_state_publisher,
        action_launch_gazebo,
        action_spawn_entity,
        launch.actions.RegisterEventHandler(
            event_handler=launch.event_handlers.OnProcessExit(
                target_action = action_spawn_entity,
                on_exit=[action_load_joint_state_controller],
            )
        ),
        launch.actions.RegisterEventHandler(
            event_handler=launch.event_handlers.OnProcessExit(
                target_action = action_load_joint_state_controller,
                on_exit=[action_load_diff_driver_controller],
            )
        ),
    ])